Method for verifying characteristics of an electron beam

ABSTRACT

A method is provided for forming a three-dimensional article through successive fusion of parts of a powder bed. The method includes the steps of: applying a first powder layer on a work table; directing an electron beam from an electron beam source over the work table, the directing of the electron beam causing the first powder layer to fuse in first selected locations according to a pre-determined model, so as to form a first part of a cross section of the three dimensional article, and intensity modulating X-rays from the powder layer or from a clean work table with a patterned aperture modulator and a patterned aperture resolver, wherein a verification of at least one of a size, position, scan speed, or shape of the electron beam is achieved by comparing detected intensity modulated X-ray signals with saved reference values.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of and claims priority to and thebenefit of U.S. Utility application Ser. No. 14/973,244, filed Dec. 17,2015, which claims priority to and the benefit of U.S. ProvisionalPatent Application Ser. No. 62/106,089, filed Jan. 21, 2015, thecontents of both of which as are hereby incorporated by reference intheir entirety.

BACKGROUND

1. Technical Field

The present invention relates to an improved method for characterizingan electron beam.

2. Related Art

Freeform fabrication or additive manufacturing is a method for formingthree-dimensional articles through successive fusion of chosen parts ofpowder layers applied to a work plate. A method and apparatus accordingto this technique is disclosed in U.S. Pat. No. 7,713,454.

Such an apparatus may comprise a work table on which thethree-dimensional article is to be formed, a powder dispenser, arrangedto lay down a thin layer of powder on the work table for the formationof a powder bed, an energy beam source for delivering an energy beamspot to the powder whereby fusion of the powder takes place, elementsfor control of the energy beam spot over the powder bed for theformation of a cross section of the three-dimensional article throughfusion of parts of the powder bed, and a controlling computer, in whichinformation is stored concerning consecutive cross sections of thethree-dimensional article. A three-dimensional article is formed throughconsecutive fusions of consecutively formed cross sections of powderlayers, successively laid down by the powder dispenser.

In order to melt the powder material at specific locations there is aneed to have an accurate control of the energy beam, such as deflectionspeed, position, and shape.

Presently an electron beam is optically calibrated using the glow of themetal. Such calibration method has several drawbacks. Firstly it is timeconsuming since it takes some time until the metal starts to glow.Secondly it requires a relatively high beam power for starting the metalto glow. Thirdly, the metal which has been glowing may have been locallydamaged or at least locally changed its material characteristics. Andlastly, the optical equipment used for the calibration may getmetallised during the calibration process or in a later process step.Furthermore there is not a straightforward relationship between the glowof the material and the power of the electron beam.

There is thus a need in the art for a simple and efficient method forcalibrating and/or verifying the characteristics of an electron beam.

BRIEF SUMMARY

An object of the present invention is to provide a method forcalibrating/verifying an electron beam which eliminates or at leastreduces the above mentioned problems. The abovementioned object isachieved via the features recited in the claims herein.

In a first aspect of the invention it is provided a method forcalibrating an electron beam, the method comprising the steps of:arranging a patterned aperture resolver having at least one opening infront of at least one X-ray detector, where the at least one opening isfacing towards the at least one X-ray detector, arranging a patternedaperture modulator between the patterned aperture resolver and asubstrate and at a predetermined distance from the patterned apertureresolver and the substrate, where the patterned aperture modulatorhaving a plurality of openings in at least a first direction, scanningan electron beam in at least a first direction on the substrate forgenerating X-rays to be received by the at least one X-ray detector,detecting the X-rays emanating from the surface produced by the scanningelectron beam with the patterned aperture modulator and the patternedaperture resolver, wherein a map of position, size and shape of theelectron beam is achieved by mapping an intensity modulation of theX-ray signal from the detector with settings for controlling theelectron beam, adjusting the settings for controlling the electron beamif the shape and/or size of the electron beam is deviating more than apredetermined value from a corresponding reference beam shape and/or areference beam size, and repeating step c-e until the shape and/or sizeof the electron beam is deviating less than a predetermined value fromthe reference beam shape and/or reference beam size.

An exemplary advantage of this method is that the calibration of theelectron beam can be performed at any moment. There may be no limitationas to whether the calibration power maybe too high or too low, since thescanning speed may be sufficiently high for not affecting the materialsurface from which the X-rays are emanating from. Another advantage isthat this kind of calibration method may be insensitive to possiblematerial deposition since the deposition may be collected by anappropriate shielding plate in front of the detector.

In another example embodiment the method further comprising the step ofrepeating step c-f for different beam powers. A non-limiting andexemplary advantage of at least this embodiment is that a fullcalibration for all beam powers can be done without risking any locallydamaged or locally changed material characteristics. Another advantageof this embodiment is that one may choose which type of pattern, 1- or2-dimensional, to use. Obviously a 1-dimensional pattern may only verifythe deflection speed in 1-dimension if not the 1-dimensional pattern isrotated and reused several times on the work table.

In still another example embodiment wherein the settings are inputsignals to a beam shaping and positioning unit. The beam shaping andpositioning unit may comprise at least one deflection coil, at least onefocus coil and at least one astigmatism coil. A non-limiting andexemplary advantage of at least this embodiment is that the size andshape of the electron beam may be calibrated by scanning the beam in atleast two different directions.

In another aspect of the present invention it is provided a device fordetecting X-rays radiated out of a substrate surface, the devicecomprising at least one first X-ray detector, a patterned apertureresolver and a patterned aperture modulator, the patterned apertureresolver with at least one opening facing towards the X-ray detector isarranged in front of the X-ray detector, the patterned aperturemodulator is provided between the patterned aperture resolver and thesubstrate at a predetermined distance from the patterned apertureresolver and the substrate, where the patterned aperture modulatorhaving a plurality of openings in at least a first direction, whereinthe x-rays from the surface is intensity modulated with the patternedaperture modulator and patterned aperture resolver before being detectedby the X-ray detector.

A non-limiting and exemplary advantage of at least this embodiment isthat such device may be used for calibrating an electron beam in anyelectron beam equipment such as: electron beam welding equipment,electron beam additive manufacturing equipment or a Scanning ElectronMicroscope.

In an example embodiment the openings in the patterned aperturemodulator and/or the patterned aperture resolver is arranged in a1-dimensional or 2-dimensional pattern. A non-limiting and exemplaryadvantage of at least this embodiment is that the modulator structuremay be designed for calibration/verification of the electron beam in oneor several directions.

In still another example embodiment of the present invention the1-dimensional or 2-dimensional pattern is periodic or non-periodic. Anon-limiting and exemplary advantage of a non-periodic pattern is thatit may make the central peak of X-ray signal on the detector stand outmore clearly among the side lobes of the X-ray signal on the samedetector. This may be more important in the case where a very largenumber of openings are used in the patterned aperture modulator and/orthe patterned aperture resolver.

In still another example embodiment of the present invention an openingat a first position of the patterned aperture modulator and/or patternedaperture resolver is arranged with a first type of micro-pattern and anopening at a second position of the patterned aperture modulator and/orpatterned aperture resolver is arranged with a second type ofmicro-pattern.

A non-limiting and exemplary advantage of at least this embodiment isthat from a single scan direction one may receive more information aboutthe beam characteristics.

In still another example embodiment of the present invention the firsttype of micro-pattern is a plurality of slots in a first direction andthe second type of micro-pattern is a plurality of slots in a seconddirection. A non-limiting and exemplary advantage of at least thisembodiment is that the X-ray signal strength may be improved while atthe same time maintaining the X-ray signal resolution.

In still another example embodiment of the present invention a basematerial of the patterned aperture modulator and the patterned apertureresolver is designed so as to shield X-ray radiation. A non-limiting andexemplary advantage of at least this embodiment is that X-ray radiationmay only reach the detector via the openings in the patterned aperturemodulator and the patterned aperture resolver.

In still another example embodiment of the present invention aprotection window is arranged between the X-ray detector and thepatterned aperture resolver or between the patterned aperture resolverand patterned aperture modulator or between the substrate and patternedaperture modulator. A non-limiting and exemplary advantage of at leastthis embodiment is that part of or the full detector may be arrangedoutside a vacuum chamber. Another advantage of this embodiment is thatthe detector may be insensitive for material deposition.

In still another example embodiment the worktable may be provided with areference pattern. A non-limiting and exemplary advantage of at leastthis embodiment is that the distance between the patterned aperturemodulator and the substrate and the patterned aperture modulator and thepatterned aperture resolver may be unknown prior to starting thecalibration/verification process. This reference pattern may determinethe scale of the detected signals.

In still another example embodiment of the present invention thepatterned aperture resolver is arranged at a distance from the X-raydetector. A non-limiting and exemplary advantage of at least thisembodiment is that the arrangement of the detector relative to thepatterned aperture resolver is relatively independent on thefunctionality of the device.

In another example embodiment of the present invention the patternedaperture resolver is replaced by a patterned detector. A non-limitingand exemplary advantage of at least this embodiment is that anyalignment procedure when manufacturing the device of the patternedaperture resolver with the patterned aperture modulator and the detectoris eliminated.

In still another example embodiment of the present invention the devicefurther comprising at least one second X-ray detector arranged with apatterned aperture resolver and a patterned aperture modulator, thepatterned aperture resolver with at least one opening facing towards theat least one second X-ray detector is arranged in front of the at leastone second X-ray detector, the patterned aperture modulator is providedbetween the patterned aperture resolver and the substrate at apredetermined distance from the patterned aperture resolver and thesubstrate, where the patterned aperture modulator having a plurality ofopenings in at least a first direction, where the x-rays from thesurface is intensity modulated with the patterned aperture modulator andthe patterned aperture resolver before being detected by the at leastone second X-ray detector, wherein the at least one first X-ray detectorand the at least one second X-ray detector are arranged at apredetermined distance from each other for detecting height variationsin a surface of the substrate.

A non-limiting and exemplary advantage of at least this embodiment isthat the substrate surface topography may be detected at the same timeas calibrating/verifying the electron beam.

In yet another example embodiment of the present invention the first andsecond x-ray detectors are arranged in a plane in parallel with thesubstrate and the height information is determined by triangulation. Anon-limiting and exemplary advantage of at least this embodiment is thatthe time difference between receiving X-rays signals by the first andsecond detectors and the order in which the first and second x-raydetectors received the x-ray signal may give an indication of thetopography if the surface. A longer time interval between X-raysemanating from the same position indicates a larger relative heightdifference. The order of receiving the signals by the first and seconddetectors may give an indication of an elevation or a cavity from anominal surface height. At the nominal surface the first and seconddetectors are receiving the X-ray signal simultaneously.

In yet another example embodiment the at least one first and the atleast one second detector are arranged in a single unit. A non-limitingand exemplary advantage of at least this embodiment is that the twodetectors may already be calibrated to each other.

In still another example embodiment the at least one first and the atleast one second detectors are arranges in a separate units. Anon-limiting and exemplary advantage of at least this embodiment is thatthe first and second detectors may be arranged to an electron beamequipment where there is sufficient space.

In another aspect of the present invention it is provided a method forforming a 3-dimensional article through successive fusion of parts of apowder bed, which parts correspond to successive cross sections of the3-dimensional article, the method comprising the steps of: providing amodel of the 3-dimensional article, applying a first powder layer on awork table, directing an electron beam from an electron beam source overthe work table, the directing of the electron beam causing the firstpowder layer to fuse in first selected locations according to the model,so as to form a first part of a cross section of the three dimensionalarticle, and intensity modulating X-rays from the powder layer or from aclean work table with a patterned aperture modulator and a patternedaperture resolver, wherein a verification of at least one of a size,position, scan speed and/or shape of the electron beam is achieved bycomparing detected intensity modulated X-ray signals with savedreference values. A non-limiting and exemplary advantage of at leastthis embodiment is that the manufacture of three-dimensional articlesmay be further improved because a verification and adjustment of theelectron beam may be performed at any given moment during themanufacture.

In still another aspect of the present invention it is provided a methodfor verifying an electron beam, the method comprising the steps of:arranging a patterned aperture resolver having at least one opening infront of at least one X-ray detector, where the at least one opening isfacing towards the at least one X-ray detector, arranging a patternedaperture modulator between the patterned aperture resolver and asubstrate and at a predetermined distance from the patterned apertureresolver and the substrate, where the patterned aperture modulatorhaving a plurality of openings in at least a first direction, scanningan electron beam in at least a first direction on the substrate forgenerating X-rays to be received by the at least one X-ray detector, andverifying at least one of a position, size and shape of the electronbeam by comparing a detected intensity modulation of the X-ray signal bythe detector with corresponding reference values, wherein the electronbeam is said to be verified if a deviation of the detected signal andthe reference value is smaller than a predetermined value. Anon-limiting and exemplary advantage of at least this method is that theverification of any electron beam may be performed for any kind ofelectron beam equipment.

The calibrating and/or the verification methods described herein abovemay be used with the additive manufacturing apparatus in which theenergy beam spot is used for fusing power material layer-wise forforming three-dimensional articles.

In another aspect of the present invention it is provided a method forcalibrating an electron beam, the method comprising the steps of:positioning a patterned aperture resolver having at least one opening infront of at least one X-ray detector, such that the at least one openingis facing towards the at least one X-ray detector; positioning apatterned aperture modulator between the patterned aperture resolver anda substrate and at a predetermined distance from the patterned apertureresolver and the substrate, where the patterned aperture modulator has aplurality of openings oriented in at least a first direction; scanningan electron beam in at least a first direction on the substrate forgenerating X-rays to be received by the at least one X-ray detector;detecting the X-rays emanating from the surface produced by the scanningelectron beam with the patterned aperture modulator and the patternedaperture resolver, wherein a map of position, size and shape of theelectron beam is achieved by mapping an intensity modulation of theX-ray signal from the detector with settings for controlling theelectron beam; adjusting the settings for controlling the electron beamif at least one of the shape or the size of the electron beam isdeviating more than a predetermined value from at least one of acorresponding reference beam shape or a reference beam size; andrepeating the scanning, detecting, and adjusting steps until at leastone of the shape or the size of the electron beam is deviating less thana predetermined value from at least one of the reference beam shape orthe reference beam size.

In another aspect of the present invention it is provided a device fordetecting X-rays radiated out of a substrate surface, the devicecomprising: at least one first X-ray detector; a patterned apertureresolver; and a patterned aperture modulator, wherein: the patternedaperture resolver includes at least one opening facing towards the X-raydetector and is positioned in front of the X-ray detector; the patternedaperture modulator is positioned between the patterned aperture resolverand the substrate at a predetermined distance from the patternedaperture resolver and the substrate, where the patterned aperturemodulator has a plurality of openings in at least a first direction; andthe x-rays from the surface are intensity modulated with the patternedaperture modulator and patterned aperture resolver before being detectedby the X-ray detector.

In another aspect of the present invention it is provided a programelement configured and arranged when executed on a computer to implementa method for calibrating an electron beam, the method comprising thesteps of: arranging a patterned aperture resolver having at least oneopening in front of at least one X-ray detector, where the at least oneopening is facing towards the at least one X-ray detector; arranging apatterned aperture modulator between the patterned aperture resolver anda substrate and at a predetermined distance from the patterned apertureresolver and the substrate, where the patterned aperture modulatorhaving a plurality of openings in at least a first direction; scanningan electron beam in at least a first direction on the substrate forgenerating X-rays to be received by the at least one X-ray detector;intensity modulating the X-rays emanating from the surface with thepatterned aperture modulator and patterned aperture resolver, wherein amap of position, size and shape of the electron beam is achieved bymapping an intensity modulated X-ray signal from the detector withsettings for controlling the electron beam; adjusting the settings forcontrolling the electron beam if the shape and/or size of the electronbeam is deviating more than a predetermined value from a correspondingreference beam shape and/or a reference beam size; and repeating thescanning, intensity modulating, and adjusting steps until the shape ofthe electron beam is deviating less than a predetermined value from areference beam shape and/or size.

In another aspect of the present invention it is provided anon-transitory computer program product comprising at least onecomputer-readable storage medium having computer-readable program codeportions embodied therein, the computer-readable program code portionscomprising: an executable portion configured for scanning an electronbeam in at least a first direction on the substrate for generatingX-rays to be received by the at least one X-ray detector; an executableportion configured for intensity modulating the X-rays emanating fromthe surface with a patterned aperture modulator and a patterned apertureresolver, wherein a map of position, size and shape of the electron beamis achieved by mapping an intensity modulated X-ray signal from thedetector with settings for controlling the electron beam; an executableportion configured for adjusting the settings for controlling theelectron beam if the shape and/or size of the electron beam is deviatingmore than a predetermined value from a corresponding reference beamshape and/or a reference beam size; and an executable portion configuredfor repeating the scanning, intensity modulating, and adjusting stepsuntil the shape of the electron beam is deviating less than apredetermined value from a reference beam shape and/or size.

In another aspect of the present invention it is provided a method forverifying an electron beam, the method comprising the steps of:arranging a patterned aperture resolver having at least one opening infront of at least one X-ray detector, where the at least one opening isfacing towards the at least one X-ray detector; arranging a patternedaperture modulator between the patterned aperture resolver and asubstrate and at a predetermined distance from the patterned apertureresolver and the substrate, where the patterned aperture modulatorhaving a plurality of openings in at least a first direction; scanningan electron beam in at least a first direction on the substrate forgenerating X-rays to be received by the at least one X-ray detector; andverifying at least one of a position, size and shape of the electronbeam by comparing a detected intensity modulation of the X-ray signal bythe detector with corresponding reference values, wherein the electronbeam is said to be verified if a deviation of the detected signal andthe reference value is smaller than a predetermined value.

In another aspect of the present invention it is provided a method forforming a 3-dimensional article through successive fusion of parts of apowder bed, which parts correspond to successive cross sections of the3-dimensional article, the method comprising the steps of: providing amodel of the 3-dimensional article; applying a first powder layer on awork table; directing an electron beam from an electron beam source overthe work table, the directing of the electron beam causing the firstpowder layer to fuse in first selected locations according to the model,so as to form a first part of a cross section of the three dimensionalarticle, and intensity modulating X-rays from the powder layer or from aclean work table with a patterned aperture modulator and a patternedaperture resolver, wherein a verification of at least one of a size,position, scan speed and/or shape of the electron beam is achieved bycomparing detected intensity modulated X-ray signals with savedreference values.

In another aspect of the present invention it is provided a programelement configured and arranged when executed on a computer to implementa method for verifying an electron beam, the method comprising the stepsof: arranging a patterned aperture resolver having at least one openingin front of at least one X-ray detector, where the at least one openingis facing towards the at least one X-ray detector; arranging a patternedaperture modulator between the patterned aperture resolver and asubstrate and at a predetermined distance from the patterned apertureresolver and the substrate, where the patterned aperture modulatorhaving a plurality of openings in at least a first direction; scanningan electron beam in at least a first direction on the substrate forgenerating X-rays to be received by the at least one X-ray detector; andverifying at least one of a position, size and shape of the electronbeam by comparing a detected intensity modulation of the X-ray signal bythe detector with corresponding reference values, wherein the electronbeam is said to be verified if a deviation of the detected signal andthe reference value is smaller than a predetermined value.

In another aspect of the present invention it is provided anon-transitory computer program product comprising at least onecomputer-readable storage medium having computer-readable program codeportions embodied therein, the computer-readable program code portionscomprising: an executable portion configured for arranging a patternedaperture resolver having at least one opening in front of at least oneX-ray detector, where the at least one opening is facing towards the atleast one X-ray detector; an executable portion configured for arranginga patterned aperture modulator between the patterned aperture resolverand a substrate and at a predetermined distance from the patternedaperture resolver and the substrate, where the patterned aperturemodulator having a plurality of openings in at least a first direction;an executable portion configured for scanning an electron beam in atleast a first direction on the substrate for generating X-rays to bereceived by the at least one X-ray detector; and an executable portionconfigured for verifying at least one of a position, size and shape ofthe electron beam by comparing a detected intensity modulation of theX-ray signal by the detector with corresponding reference values,wherein the electron beam is said to be verified if a deviation of thedetected signal and the reference value is smaller than a predeterminedvalue.

Herein and throughout, where an exemplary embodiment is described or anadvantage thereof is identified, such are considered and intended asexemplary and non-limiting in nature, so as to not otherwise limit orconstrain the scope and nature of the inventive concepts disclosed.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

The invention will be further described in the following, in anon-limiting way with reference to the accompanying drawings. Samecharacters of reference are employed to indicate corresponding similarparts throughout the several figures of the drawings:

FIG. 1 depicts a schematic side view of a first example embodiment of adevice for calibrating/verifying an electron beam;

FIGS. 2A and 2B depict schematic side views of two example embodimentsof patterned aperture modulator and patterned aperture resolver setupsin the device for calibrating/verifying an electron beam;

FIG. 3 depicts an apparatus in which the inventive device and method maybe implemented;

FIG. 4 depicts a schematic flow chart of an inventive method accordingto an embodiment of the present invention;

FIG. 5 depicts a schematic side view of a first example embodiment of atwo detector device for calibrating/verifying an electron beam;

FIG. 6 depicts a schematic side view of a first example embodiment of adetector array device for calibrating/verifying an electron beam;

FIG. 7 depicts a schematic side view of how the size and shape of anelectron beam may be calibrated/verified with an X-ray detector apatterned aperture resolver and a patterned aperture modulator;

FIG. 8 is a block diagram of an exemplary system 1020 according tovarious embodiments;

FIG. 9A is a schematic block diagram of a server 1200 according tovarious embodiments; and

FIG. 9B is a schematic block diagram of an exemplary mobile device 1300according to various embodiments.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

Various example embodiments of the present invention will now bedescribed more fully hereinafter with reference to the accompanyingdrawings, in which some, but not all embodiments of the invention areshown. Indeed, embodiments of the invention may be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will satisfy applicable legal requirements. Unlessotherwise defined, all technical and scientific terms used herein havethe same meaning as commonly known and understood by one of ordinaryskill in the art to which the invention relates. The term “or” is usedherein in both the alternative and conjunctive sense, unless otherwiseindicated. Like numbers refer to like elements throughout.

To facilitate the understanding of this invention, a number of terms aredefined below. Terms defined herein have meanings as commonly understoodby a person of ordinary skill in the areas relevant to the presentinvention. Terms such as “a”, “an” and “the” are not intended to referto only a singular entity, but include the general class of which aspecific example may be used for illustration. The terminology herein isused to describe specific embodiments of the invention, but their usagedoes not delimit the invention, except as outlined in the claims.

The term “three-dimensional structures” and the like as used hereinrefer generally to intended or actually fabricated three-dimensionalconfigurations (e.g. of structural material or materials) that areintended to be used for a particular purpose. Such structures, etc. may,for example, be designed with the aid of a three-dimensional CAD system.

The term “electron beam” as used herein in various embodiments refers toany charged particle beam. The sources of a charged particle beam caninclude an electron gun, a linear accelerator and so on.

FIG. 3 depicts an example embodiment of a freeform fabrication oradditive manufacturing apparatus 300 in which the inventivecalibration/verification method and calibration/verification device maybe implemented. The inventive calibration/verification method and devicemay also be implemented in a Scanning Electron Microscopy (SEM), anelectron welding equipment or other scanning electron beam equipment.

The apparatus 300 comprising an electron gun 302; two powder hoppers306, 307; a start plate 316; a build tank 312; a powder distributor 310;a build platform 314; a vacuum chamber 320, a control unit 350 and acalibration device 360.

The vacuum chamber 320 is capable of maintaining a vacuum environment bymeans of a vacuum system, which system may comprise a turbomolecularpump, a scroll pump, an ion pump and one or more valves which are wellknown to a skilled person in the art and therefore need no furtherexplanation in this context. The vacuum system may be controlled by acontrol unit 350.

The electron gun 302 is generating an electron beam 370 which may beused for melting or fusing together powder material 318 provided on thestart plate 316. The electron gun 302 may be provided in the vacuumchamber 320. The control unit 350 may be used for controlling andmanaging the electron beam emitted from the electron beam gun 302. Atleast one focusing coil (not shown), at least one deflection coil (notshown) and an electron beam power supply (not shown) may be electricallyconnected to the control unit 350. In an example embodiment of theinvention the electron gun 302 generates a focusable electron beam withan accelerating voltage of about 60 kV and with a beam power in therange of 0-10 kW. The pressure in the vacuum chamber may be in the rangeof 1×10⁻³−1×10⁻⁶ mBar when building the three-dimensional article byfusing the powder layer by layer with the energy beam.

The powder hoppers 306, 307 comprise the powder material to be providedon the start plate 316 in the build tank 312. The powder material mayfor instance be pure metals or metal alloys such as titanium, titaniumalloys, aluminum, aluminum alloys, stainless steel, Co—Cr—W alloy, etc.

The powder distributor 310 is arranged to lay down a thin layer of thepowder material on the start plate 316. During a work cycle the buildplatform 314 will be lowered successively in relation to the ray gunafter each added layer of powder material. In order to make thismovement possible, the build platform 314 is in one embodiment of theinvention arranged movably in vertical direction, i.e., in the directionindicated by arrow P. This means that the build platform 314 starts inan initial position, in which a first powder material layer of necessarythickness has been laid down on the start plate 316. A first layer ofpowder material may be thicker than the other applied layers. The reasonfor starting with a first layer which is thicker than the other layersis that one does not want a melt-through of the first layer onto thestart plate. The build platform is thereafter lowered in connection withlaying down a new powder material layer for the formation of a new crosssection of a three-dimensional article. Means for lowering the buildplatform 314 may for instance be through a servo engine equipped with agear, adjusting screws etc.

A model of the three dimensional article may be generated via a CAD(Computer Aided Design) tool.

After a first layer is finished, i.e., the fusion of powder material formaking a first layer of the three-dimensional article, a second powderlayer is provided on the work table 316. The second powder layer ispreferably distributed according to the same manner as the previouslayer. However, there might be alternative methods in the same additivemanufacturing machine for distributing powder onto the work table. Forinstance, a first layer may be provided by means of a first powderdistributor, a second layer may be provided by another powderdistributor. The design of the powder distributor is automaticallychanged according to instructions from the control unit. A powderdistributor in the form of a single rake system, i.e., where one rake iscatching powder fallen down from both a left powder hopper 306 and aright powder hopper 307, the rake as such can change design.

After having distributed the second powder layer on the work table 316,the energy beam is directed over the work table causing the secondpowder layer to fuse in selected locations to form a second crosssection of the three-dimensional article. Fused portions in the secondlayer may be bonded to fused portions of the first layer. The fusedportions in the first and second layer may be melted together by meltingnot only the powder in the uppermost layer but also remelting at least afraction of a thickness of a layer directly below the uppermost layer.

FIG. 1 depicts a schematic side view of a first example embodiment of adevice 100 for calibrating/verifying an electron beam 110. The device100 comprises a modulator patterned aperture 130, a resolver patternedaperture 140 and at least one X-ray detector 150.

The modulator patterned aperture 130 is provided at a predetermineddistance B from the resolver patterned aperture 140. The modulatorpatterned aperture 130 comprises a plurality of openings 131-137. Theopenings may be provided in a regular pattern or irregular pattern. Thedimension of the openings is in the range of 1-10 000 μm. The openingsmay have a circular shape, rectangular shape or a slit shape. Theopenings may be arranged in 1-dimension or 2-dimensions.

Different openings of the patterned aperture 130 may be provided withdifferent types of micro-pattern. A first opening may have a first typeof micro-pattern and a second opening may have a second type ofmicro-pattern. The first type of micro pattern may be a plurality ofslits in a first direction. The second type of micro-pattern may be aplurality of slits in a second direction.

The resolver patterned aperture 140 comprises at least one opening 145.The at least one opening 145 may have a dimension in the range of 1-10000 μm. The at least one opening 145 may have a circular shape,rectangular shape or a slit shape.

In case of a plurality of openings in the resolver patterned aperture140, the openings may be arranged in 1-dimension or 2-dimensions.

An opening in the resolver patterned aperture 140 may be provided with amicro pattern. The micro pattern may be a 1 dimensional or 2-dimensionalpattern of circular, rectangular or slit shaped openings.

Different openings of the resolver patterned aperture 140 may beprovided with different types of micro-pattern. A first opening may havea first type of micro-pattern and a second opening may have a secondtype of micro-pattern. The first type of micro pattern may be aplurality of slits in a first direction. The second type ofmicro-pattern may be a plurality of slits in a second direction.

The modulator patterned aperture 130 may be provided at a predetermineddistance A from a substrate 170. In case the distance A is unknown, areference pattern may be provided on the substrate 170 for achieving acorrect scale of the distance between different detected positions onthe substrate 170. In case the distance A is well defined, the referencepattern may become unnecessary since the scale is determined by thedistances A, B and the dimension of the modulator patterned aperture 130and the resolver patterned aperture 140. Distance B may be between100-500 mm. Distance A may be 300-1000 mm. Distance D may be 10-100 mmand distance C may be 100-1000 mm.

An electron beam impinging on the substrate 170 will create X-rayradiation 120 radiating in all backward directions, i.e., in a directionout of the top surface of the substrate 170 into the ambient environment(vacuum chamber). This backward radiation is illustrated in FIG. 1 withsmall arrows in all direction around the first position 171 of thesubstrate 170 where the electron beam 110 is illustrated to impinge.

X-rays emanating from the first position 171 of the substrate 170 withina small angle interval is allowed to pass through a first opening 131 inthe modulator patterned aperture 130 via the at least one opening 145 inthe resolver patterned aperture 140 to the X-ray detector 150.

By moving the electron beam to a second position 172 of the substrate170, X-rays emanating from the second position 172 of the substrate 170within a small angle interval is allowed to pass through a secondopening 132 in the modulator patterned aperture 130 via the at least oneopening 145 in the resolver patterned aperture 140 to the X-ray detector150.

In the same manner X-rays emanating from the third to the seventhposition 173-177 on the substrate 170 are allowed to reach the X-raydetector 150 via the patterned aperture resolver 140 and a correspondingopening 133-137 of the patterned aperture modulator 130.

The electron beam position may be calibrated by detecting the modulatedX-ray signal by the X-ray detector from at least two different positions171-177 on the substrate 170. If the distance A is known and thedistance between individual openings in the patterned aperture modulator130 prior to the calibration process, the detected x-rays in combinationwith the setting of a beam shaping and positioning unit will determinethe actual position of the electron beam.

The beam shaping and positioning unit may comprise at least onedeflection coil, at least one focus coil and at least one astigmatismsoil.

The scan speed may be determined by detecting the time between twopredetermined signals emanating from two different positions 131-137 onthe patterned aperture modulator 130. If the deflecting coil is providedwith a constant signal and since the distance between individualopenings in the patterned aperture modulator is known, the scan speedmay easily be calculated.

The size and shape of the electron beam may be determined by analyzingthe intensity modulated signal. As the electron beam is deflected on thesubstrate the X-rays from the substrate will more or less be detected bya predetermined opening in the patterned aperture modulator and apredetermined opening in the patterned aperture resolver. Informationabout the electron beam size and shape may be determined from theintensity modulated signal as it passes over an edge of the opening. Thetime duration an X-ray signal is detected by a predetermined position onthe detector may be proportional to the size of the electron beam spotin the deflection direction. In order to determine a size and shape ofthe electron beam spot in another direction the deflection direction hasto be changed. By analyzing the x-ray signal on a predetermined positionon the detector for at least two deflection directions, one is providedwith information of the beam size and shape in the two directions. Byusing more deflection directions the accuracy of the beam shape may beimproved.

FIG. 7 depicts a schematic side view of how the size and shape of anelectron beam may be calibrated/verified with an X-ray detector, apatterned aperture resolver and a patterned aperture modulator. Theelectron beam in this illustration is assumed to have a rectangularshape. Obviously any desired shape of the electron beam may be used butthis rectangular shape is used for simplifying the illustration only. Asa rectangular beam is scanned over the surface 770 X-ray signalsemanating from the impinging position on the substrate may reach thedetector 750. When the electron beam is scanned in the direction givenby the arrow in the figure a signal of the square shaped electron beamwill be as the dotted FIG. 760 in front of the patterned apertureresolver 740. The sloped portions of the figure represents an X-raysignal partially hidden by an opening 735 in a pattern aperturemodulator 730. By analyzing the shape of the detected intensitymodulated signal received by the detector 750 one may be able todetermine the shape of the beam in the direction of deflection.

FIG. 2A depicts a schematic side view of a first example embodiment of apatterned aperture modulator and patterned aperture resolver setup inthe device for calibrating/verifying an electron beam. In thisembodiment the patterned aperture modulator 230 comprises a first set ofapertures 237 and a second set of apertures 238. The first set ofapertures 237 comprises 3 openings 231, 232, 233 regularly spaced fromeach other. The second set of apertures 238 comprises three openings234, 235, 236 regularly spaced from each other. The first and secondsets of apertures 237, 238 are arranged at a distance from each otherwhich is larger than the individual distance between two openings in oneof the first or second set of apertures 237, 238, i.e., the distancebetween openings 233 and 234 is larger than the distance between 231 and232 or the distance between 235 and 236. In certain embodiments, thepatterned aperture resolver comprises three openings 241, 242, 243.

As the electron beam is deflected over the substrate 270 X-rays arecreated which will travel in the direction towards the detector 250.Only some of the will hit the detector because of the arrangement withthe patterned aperture modulator 230 and the patterned aperture resolverin front of the detector.

As the electron beam hits position 271 a only a small portion of thex-rays created at this position will hit the detector, which isillustrated by the single dotted line. This small portion will hit therightmost position of the detector 250 since it goes via opening 231 inthe patterned aperture modulator 230 and a third opening 243 in thepatterned aperture resolver 240.

When the electron beam hits position 272 a a somewhat larger portion ofthe X-rays will pass through the patterned aperture modulator 230 andthe patterned aperture resolver 240 which is indicated by two dottedlines from position 272 a. A first line will pass through opening 231and opening 242 to a middle position on the detector 250. A second linewill pass through opening 232 and opening 243 to a rightmost position onthe detector 250.

When the electron beam hits position 273 a a maximum portion of theX-rays from a first area 278 will pass through the patterned aperturemodulator 230 and the patterned aperture resolver 240 which is indicatedby three dotted lines from position 273 a. A first line will passthrough opening 231 and opening 241 to a leftmost position on thedetector 250. A second line will pass through opening 232 and opening242 to a middle position on the detector 250. A third line will passthrough opening 233 and opening 243 to a rightmost position on thedetector 250.

When the electron beam hits position 274 a the amount of X-rays reachingthe detector is decreased compared with position 273 a. And when theelectron beam hits position 275 a the amount of X-rays reaching thedetector is further reduced to be smaller compared to position 274 a.

Each of position 271 a-275 a in the first area 278 may be used fordetermining the position, size, shape and speed of the electron beam,where 273 a would be the main peak and 271 a, 272 a, 274 a, 275 a areside lobes that may or may not be used for calibration/verificationpurposes. The difference between the positions 271 a-275 a in the firstarea 278 are the amount of X-ray signals which is received by thedetector.

An exemplary advantage of a plurality of openings in the patternedaperture modulator and patterned aperture resolver may be to increasethe detected signal while maintaining the resolution of the detectedX-ray signal.

X-rays emanating from the first area 278 of the substrate 270 will passthrough a first set of openings 237 in the patterned aperture modulator230.

X-rays emanating from a second area 279 of the substrate 270 will beallowed to pass through a second set of openings in the patternedaperture modulator 230. In this embodiment the first set of openings 237is equal to the second set of opening, i.e., the number of openings, thesize and shape of the openings in the first set 237 is identical to thesecond set 238. For this reason a signal strength pattern of the x-raysfrom different positions 271 a-275 a in the first area 278 of thesubstrate 270 will be identical to a signal strength pattern of thex-rays from different positions 271 b-275 b in the second area 279 ofthe substrate 270.

FIG. 2B depicts a schematic side view of a second example embodiment ofa patterned aperture modulator and patterned aperture resolver setup inthe device for calibrating/verifying an electron beam. In this secondembodiment a patterned aperture resolver 240′ is provided with anirregular pattern of openings 241′, 242′, 243′. A patterned aperturemodulator 230′ is also provided with an irregular pattern of openings231′, 232′, 233′.

By arranging irregular patterns of openings in at least one of thepatterned aperture modulator and/or the pattern aperture resolver theratio of the signal strength between a position where the detector 250is detecting X-ray signals from each of the openings in the patternedaperture modulator 230′ and a position in which only some of theopenings in the patterned aperture detector 230′ is increased, i.e., thedifference between full strength signal and semi full strength signal isincreased by changing at least one of the patterned aperture modulatorand/or patterned aperture resolver to an irregular pattern instead of aregular pattern.

The opening may have any type of shape including but not limited to,rectangular, circular, elliptical, square, triangular, hexagonal or slotformed. The intent of using irregular pattern is to make the centralpeak standing out among the side lobes. This may be advantageous in acase where a large number of openings are used.

FIG. 5 illustrates an embodiment in which a first detector 510 and asecond detector 520 are used. The first detector 510 and the seconddetector 520 are arranged at a predetermined distance M from each other.The first detector 510 is provided with a first patterned apertureresolver 515. FIG. 5 shows only a single beam to increase the clarity ofthe embodiment, but an actual system may use techniques similar to FIG.2A or FIG. 2B. The second detector 520 is provided with a secondpatterned aperture resolver 525. The first and second detectors 510, 520are provided in a first plane in parallel with a substrate 570. Thefirst and second patterned aperture resolvers 515, 525 are provided in asecond plane in parallel with the substrate 570. The first and secondplane may be arranged at a predetermined distance from each other. In anexample embodiment the first and second plane are the same, i.e., thepatterned aperture resolver is attached onto the detector or the firstdetector 510 and the second detector are 1-dimensional or 2-dimensionalarrays of separate detectors.

A first patterned aperture modulator 530 is provided at a predetermineddistance Q from a second patterned aperture modulator 540. The first andsecond patterned aperture modulators 530, 540 are provided in a thirdplane in parallel with the substrate 570. The third plane is provided ata predetermined distance P from the second plane. The third plane isprovided at a predetermined distance R from the substrate 570.

An arrangement with two detectors arranged in a plane in parallel withthe substrate according to FIG. 5 may not only be used forcalibrating/verifying the position, size, shape and speed of an electronbeam in an X-Y plane at a surface of a substrate but also be used fordetecting the topography of the surface of the substrate 570.

As indicated in the graph to the left of the two-detector setup, wherethe X-ray signal is on the Y-axis and the time is on the x-axis, aspecific time difference between detectors A-B may correspond to aspecific height. In the setup according to FIG. 5 there is only onepoint on the substrate 570 where an X-ray signal may reach the firstdetector 510 and the second detector 520 at the same time, this may be anominal height of the substrate 570. If the first detector 510 isreceiving the X-ray signal before the second detector 520 it is I anindication of a substrate point above the nominal height. In contrary,if the second detector 520 is receiving the X-ray signal before thefirst detector 510 it is an indication of a substrate point below thenominal height.

In order to cover a larger area of the substrate than just one positionand to increase the detected signal, a number of openings may beprovided in the first and second patterned aperture modulators 530, 540.

In still another example embodiment the at least first and secondpatterned aperture modulators are provided with a plurality of openingsand the first and second patterned aperture resolvers 515, 525 areprovided with a plurality of openings. In another example embodiment theplurality of openings in at least one of the patterned apertureresolvers are substituted with an array, 1-dimensional or 2-dimensional,of detectors.

In FIG. 6 it is illustrated a schematic side view of another exampleembodiment of a patterned aperture modulator 640 and patterned apertureresolver 630 setup in the device 600 for calibrating/verifying anelectron beam. In this embodiment the detector is a detector array in1-dimension or 2-dimensions. In the illustrated setup the detector array650 will cover X-ray images from at least two positions on the substrate670. If the detector array is 1-dimensional, the X-ray image is a1-dimensional image of the electron beam. If the detector array is2-dimensional, the X-ray image is a 2-dimensional image of the electronbeam. The number of detectors in the array and the size of the detectorswill determine the resolution of the X-ray image.

If the deflection speed is determined to be out of specification awarning signal may be sent to the operator of the machine. In analternative embodiment when the deflection speed is determined to be outof specification the additive manufacturing machine may be switched offor put in an idle state.

In certain embodiments, the work piece may be provided with a referencepattern. This reference pattern may be used for calibrating the scanspeed and relative position but also for detecting other deviations inthe energy beam train.

The electron beam source is used for generating an electron beam 260which may be deflected on the work table 250 by means of at least onedeflection coil (not shown). By changing the magnetic field of thedeflection coil the electron beam 260 may be moved at any desiredposition within a predetermined maximum area.

The deflection speed of the electron beam may be altered by changing themagnetic field of the deflection coil, i.e., by ramping the electricalcurrent in the deflection coil at different speeds, where a higherramping speed will result in a larger deflection speed than a lowerramping speed. The verification of the deflection speed is identical aspreviously described in relation to FIG. 1. The only difference betweenFIGS. 1 and 2 is the energy beam source and how the energy beam isdeflected.

FIG. 4 depicts a schematic flow chart of an inventive method accordingto an embodiment of the present invention. In the method a 3-dimensionalarticle is formed through successive fusion of parts of a powder bed,which parts correspond to successive cross sections of the 3-dimensionalarticle.

In a first step, denoted by 410, a model of the 3-dimensional article isprovided. The model may be generated by a suitable CAD-tool.

In a second step, denoted by 420, a first powder layer is applied on awork table.

In a third step, denoted by 430, an electron beam from an electron beamsource is directed over the work table. The directing of the electronbeam causing the first powder layer to fuse in first selected locationsaccording to the model, so as to form a first part of a cross section ofthe three dimensional article.

In a fourth step, denoted by 440, intensity modulating X-rays from thepowder layer or from a clean work table with a patterned aperturemodulator and a patterned aperture resolver, wherein a verification ofat least one of a size, position, scan speed and/or shape of theelectron beam is achieved by comparing detected intensity modulatedX-ray signals with saved reference values. The saved reference valuesmay have been created when the machine was new. The reference values mayhave been created at any time earlier in the lifetime of the additivemanufacturing machine.

In the illustrated examples above, the patterned aperture modulatorand/or the patterned aperture resolver may be manufactured from amaterial which efficiently may shield from X-ray radiation, such aslead, brass, copper or other metals with high atomic numbers or alloystherefrom. In an example embodiment the patterned aperture modulatorand/or the patterned aperture resolver may be made of a material with arelatively low atomic number such as aluminium and thereafter coveredwith another material having a high atomic number such as gold orcopper.

In another aspect of the invention it is provided a program elementconfigured and arranged when executed on a computer forcalibrating/verifying a position, size, shape and deflection speed of anenergy beam spot. The program element may specifically be configured toperform the steps of: arranging a patterned aperture resolver having atleast one opening in front of at least one X-ray detector, where the atleast one opening is facing towards the at least one X-ray detector,arranging a patterned aperture modulator between the patterned apertureresolver and a substrate and at a predetermined distance from thepatterned aperture resolver and the substrate, where the patternedaperture modulator having a plurality of openings in at least a firstdirection, scanning an electron beam in at least a first direction onthe substrate for generating X-rays to be received by the at least oneX-ray detector, intensity modulating the X-rays emanating from thesurface with the patterned aperture modulator and patterned apertureresolver, wherein a map of position, size and shape of the electron beamis achieved by mapping an intensity modulated X-ray signal from thedetector with settings for controlling the electron beam, adjusting thesettings for controlling the electron beam if the shape and/or size ofthe electron beam is deviating more than a predetermined value from acorresponding reference beam shape and/or a reference beam size, andrepeating step c-e until the shape of the electron beam is deviatingless than a predetermined value from a reference beam shape.

The program element may be installed in a computer readable storagemedium. The computer readable storage medium may be the control unit 350or another distinct and separate control unit, as may be desirable. Thecomputer readable storage medium and the program element, which maycomprise computer-readable program code portions embodied therein, mayfurther be contained within a non-transitory computer program product.Further details regarding these features and configurations areprovided, in turn, below.

As mentioned, various embodiments of the present invention may beimplemented in various ways, including as non-transitory computerprogram products. A computer program product may include anon-transitory computer-readable storage medium storing applications,programs, program modules, scripts, source code, program code, objectcode, byte code, compiled code, interpreted code, machine code,executable instructions, and/or the like (also referred to herein asexecutable instructions, instructions for execution, program code,and/or similar terms used herein interchangeably). Such non-transitorycomputer-readable storage media include all computer-readable media(including volatile and non-volatile media).

In one embodiment, a non-volatile computer-readable storage medium mayinclude a floppy disk, flexible disk, hard disk, solid-state storage(SSS) (e.g., a solid state drive (SSD), solid state card (SSC), solidstate module (SSM)), enterprise flash drive, magnetic tape, or any othernon-transitory magnetic medium, and/or the like. A non-volatilecomputer-readable storage medium may also include a punch card, papertape, optical mark sheet (or any other physical medium with patterns ofholes or other optically recognizable indicia), compact disc read onlymemory (CD-ROM), compact disc compact disc-rewritable (CD-RW), digitalversatile disc (DVD), Blu-ray disc (BD), any other non-transitoryoptical medium, and/or the like. Such a non-volatile computer-readablestorage medium may also include read-only memory (ROM), programmableread-only memory (PROM), erasable programmable read-only memory (EPROM),electrically erasable programmable read-only memory (EEPROM), flashmemory (e.g., Serial, NAND, NOR, and/or the like), multimedia memorycards (MMC), secure digital (SD) memory cards, SmartMedia cards,CompactFlash (CF) cards, Memory Sticks, and/or the like. Further, anon-volatile computer-readable storage medium may also includeconductive-bridging random access memory (CBRAM), phase-change randomaccess memory (PRAM), ferroelectric random-access memory (FeRAM),non-volatile random-access memory (NVRAM), magnetoresistiverandom-access memory (MRAM), resistive random-access memory (RRAM),Silicon-Oxide-Nitride-Oxide-Silicon memory (SONOS), floating junctiongate random access memory (FJG RAM), Millipede memory, racetrack memory,and/or the like.

In one embodiment, a volatile computer-readable storage medium mayinclude random access memory (RAM), dynamic random access memory (DRAM),static random access memory (SRAM), fast page mode dynamic random accessmemory (FPM DRAM), extended data-out dynamic random access memory (EDODRAM), synchronous dynamic random access memory (SDRAM), double datarate synchronous dynamic random access memory (DDR SDRAM), double datarate type two synchronous dynamic random access memory (DDR2 SDRAM),double data rate type three synchronous dynamic random access memory(DDR3 SDRAM), Rambus dynamic random access memory (RDRAM), TwinTransistor RAM (TTRAM), Thyristor RAM (T-RAM), Zero-capacitor (Z-RAM),Rambus in-line memory module (RIMM), dual in-line memory module (DIMM),single in-line memory module (SIMM), video random access memory VRAM,cache memory (including various levels), flash memory, register memory,and/or the like. It will be appreciated that where embodiments aredescribed to use a computer-readable storage medium, other types ofcomputer-readable storage media may be substituted for or used inaddition to the computer-readable storage media described above.

As should be appreciated, various embodiments of the present inventionmay also be implemented as methods, apparatus, systems, computingdevices, computing entities, and/or the like, as have been describedelsewhere herein. As such, embodiments of the present invention may takethe form of an apparatus, system, computing device, computing entity,and/or the like executing instructions stored on a computer-readablestorage medium to perform certain steps or operations. However,embodiments of the present invention may also take the form of anentirely hardware embodiment performing certain steps or operations.

Various embodiments are described below with reference to block diagramsand flowchart illustrations of apparatuses, methods, systems, andcomputer program products. It should be understood that each block ofany of the block diagrams and flowchart illustrations, respectively, maybe implemented in part by computer program instructions, e.g., aslogical steps or operations executing on a processor in a computingsystem. These computer program instructions may be loaded onto acomputer, such as a special purpose computer or other programmable dataprocessing apparatus to produce a specifically-configured machine, suchthat the instructions which execute on the computer or otherprogrammable data processing apparatus implement the functions specifiedin the flowchart block or blocks.

These computer program instructions may also be stored in acomputer-readable memory that can direct a computer or otherprogrammable data processing apparatus to function in a particularmanner, such that the instructions stored in the computer-readablememory produce an article of manufacture including computer-readableinstructions for implementing the functionality specified in theflowchart block or blocks. The computer program instructions may also beloaded onto a computer or other programmable data processing apparatusto cause a series of operational steps to be performed on the computeror other programmable apparatus to produce a computer-implementedprocess such that the instructions that execute on the computer or otherprogrammable apparatus provide operations for implementing the functionsspecified in the flowchart block or blocks.

Accordingly, blocks of the block diagrams and flowchart illustrationssupport various combinations for performing the specified functions,combinations of operations for performing the specified functions andprogram instructions for performing the specified functions. It shouldalso be understood that each block of the block diagrams and flowchartillustrations, and combinations of blocks in the block diagrams andflowchart illustrations, could be implemented by special purposehardware-based computer systems that perform the specified functions oroperations, or combinations of special purpose hardware and computerinstructions.

FIG. 8 is a block diagram of an exemplary system 1020 that can be usedin conjunction with various embodiments of the present invention. In atleast the illustrated embodiment, the system 1020 may include one ormore central computing devices 1110, one or more distributed computingdevices 1120, and one or more distributed handheld or mobile devices1300, all configured in communication with a central server 1200 (orcontrol unit) via one or more networks 1130. While FIG. 8 illustratesthe various system entities as separate, standalone entities, thevarious embodiments are not limited to this particular architecture.

According to various embodiments of the present invention, the one ormore networks 1130 may be capable of supporting communication inaccordance with any one or more of a number of second-generation (2G),2.5G, third-generation (3G), and/or fourth-generation (4G) mobilecommunication protocols, or the like. More particularly, the one or morenetworks 1130 may be capable of supporting communication in accordancewith 2G wireless communication protocols IS-136 (TDMA), GSM, and IS-95(CDMA). Also, for example, the one or more networks 1130 may be capableof supporting communication in accordance with 2.5G wirelesscommunication protocols GPRS, Enhanced Data GSM Environment (EDGE), orthe like. In addition, for example, the one or more networks 1130 may becapable of supporting communication in accordance with 3G wirelesscommunication protocols such as Universal Mobile Telephone System (UMTS)network employing Wideband Code Division Multiple Access (WCDMA) radioaccess technology. Some narrow-band AMPS (NAMPS), as well as TACS,network(s) may also benefit from embodiments of the present invention,as should dual or higher mode mobile stations (e.g., digital/analog orTDMA/CDMA/analog phones). As yet another example, each of the componentsof the system 1020 may be configured to communicate with one another inaccordance with techniques such as, for example, radio frequency (RF),Bluetooth™ infrared (IrDA), or any of a number of different wired orwireless networking techniques, including a wired or wireless PersonalArea Network (“PAN”), Local Area Network (“LAN”), Metropolitan AreaNetwork (“MAN”), Wide Area Network (“WAN”), or the like.

Although the device(s) 1110-1300 are illustrated in FIG. 8 ascommunicating with one another over the same network 1130, these devicesmay likewise communicate over multiple, separate networks.

According to one embodiment, in addition to receiving data from theserver 1200, the distributed devices 1110, 1120, and/or 1300 may befurther configured to collect and transmit data on their own. In variousembodiments, the devices 1110, 1120, and/or 1300 may be capable ofreceiving data via one or more input units or devices, such as a keypad,touchpad, barcode scanner, radio frequency identification (RFID) reader,interface card (e.g., modem, etc.) or receiver. The devices 1110, 1120,and/or 1300 may further be capable of storing data to one or morevolatile or non-volatile memory modules, and outputting the data via oneor more output units or devices, for example, by displaying data to theuser operating the device, or by transmitting data, for example over theone or more networks 1130.

In various embodiments, the server 1200 includes various systems forperforming one or more functions in accordance with various embodimentsof the present invention, including those more particularly shown anddescribed herein. It should be understood, however, that the server 1200might include a variety of alternative devices for performing one ormore like functions, without departing from the spirit and scope of thepresent invention. For example, at least a portion of the server 1200,in certain embodiments, may be located on the distributed device(s)1110, 1120, and/or the handheld or mobile device(s) 1300, as may bedesirable for particular applications. As will be described in furtherdetail below, in at least one embodiment, the handheld or mobiledevice(s) 1300 may contain one or more mobile applications 1330 whichmay be configured so as to provide a user interface for communicationwith the server 1200, all as will be likewise described in furtherdetail below.

FIG. 9A is a schematic diagram of the server 1200 according to variousembodiments. The server 1200 includes a processor 1230 that communicateswith other elements within the server via a system interface or bus1235. Also included in the server 1200 is a display/input device 1250for receiving and displaying data. This display/input device 1250 maybe, for example, a keyboard or pointing device that is used incombination with a monitor. The server 1200 further includes memory1220, which typically includes both read only memory (ROM) 1226 andrandom access memory (RAM) 1222. The server's ROM 1226 is used to storea basic input/output system 1224 (BIOS), containing the basic routinesthat help to transfer information between elements within the server1200. Various ROM and RAM configurations have been previously describedherein.

In addition, the server 1200 includes at least one storage device orprogram storage 210, such as a hard disk drive, a floppy disk drive, aCD Rom drive, or optical disk drive, for storing information on variouscomputer-readable media, such as a hard disk, a removable magnetic disk,or a CD-ROM disk. As will be appreciated by one of ordinary skill in theart, each of these storage devices 1210 are connected to the system bus1235 by an appropriate interface. The storage devices 1210 and theirassociated computer-readable media provide nonvolatile storage for apersonal computer. As will be appreciated by one of ordinary skill inthe art, the computer-readable media described above could be replacedby any other type of computer-readable media known in the art. Suchmedia include, for example, magnetic cassettes, flash memory cards,digital video disks, and Bernoulli cartridges.

Although not shown, according to an embodiment, the storage device 1210and/or memory of the server 1200 may further provide the functions of adata storage device, which may store historical and/or current deliverydata and delivery conditions that may be accessed by the server 1200. Inthis regard, the storage device 1210 may comprise one or more databases.The term “database” refers to a structured collection of records or datathat is stored in a computer system, such as via a relational database,hierarchical database, or network database and as such, should not beconstrued in a limiting fashion.

A number of program modules (e.g., exemplary modules 1400-1700)comprising, for example, one or more computer-readable program codeportions executable by the processor 1230, may be stored by the variousstorage devices 1210 and within RAM 1222. Such program modules may alsoinclude an operating system 1280. In these and other embodiments, thevarious modules 1400, 1500, 1600, 1700 control certain aspects of theoperation of the server 1200 with the assistance of the processor 1230and operating system 1280. In still other embodiments, it should beunderstood that one or more additional and/or alternative modules mayalso be provided, without departing from the scope and nature of thepresent invention.

In various embodiments, the program modules 1400, 1500, 1600, 1700 areexecuted by the server 1200 and are configured to generate one or moregraphical user interfaces, reports, instructions, and/ornotifications/alerts, all accessible and/or transmittable to varioususers of the system 1020. In certain embodiments, the user interfaces,reports, instructions, and/or notifications/alerts may be accessible viaone or more networks 1130, which may include the Internet or otherfeasible communications network, as previously discussed.

In various embodiments, it should also be understood that one or more ofthe modules 1400, 1500, 1600, 1700 may be alternatively and/oradditionally (e.g., in duplicate) stored locally on one or more of thedevices 1110, 1120, and/or 1300 and may be executed by one or moreprocessors of the same. According to various embodiments, the modules1400, 1500, 1600, 1700 may send data to, receive data from, and utilizedata contained in one or more databases, which may be comprised of oneor more separate, linked and/or networked databases.

Also located within the server 1200 is a network interface 1260 forinterfacing and communicating with other elements of the one or morenetworks 1130. It will be appreciated by one of ordinary skill in theart that one or more of the server 1200 components may be locatedgeographically remotely from other server components. Furthermore, oneor more of the server 1200 components may be combined, and/or additionalcomponents performing functions described herein may also be included inthe server.

While the foregoing describes a single processor 1230, as one ofordinary skill in the art will recognize, the server 1200 may comprisemultiple processors operating in conjunction with one another to performthe functionality described herein. In addition to the memory 1220, theprocessor 1230 can also be connected to at least one interface or othermeans for displaying, transmitting and/or receiving data, content or thelike. In this regard, the interface(s) can include at least onecommunication interface or other means for transmitting and/or receivingdata, content or the like, as well as at least one user interface thatcan include a display and/or a user input interface, as will bedescribed in further detail below. The user input interface, in turn,can comprise any of a number of devices allowing the entity to receivedata from a user, such as a keypad, a touch display, a joystick or otherinput device.

Still further, while reference is made to the “server” 1200, as one ofordinary skill in the art will recognize, embodiments of the presentinvention are not limited to traditionally defined server architectures.Still further, the system of embodiments of the present invention is notlimited to a single server, or similar network entity or mainframecomputer system. Other similar architectures including one or morenetwork entities operating in conjunction with one another to providethe functionality described herein may likewise be used withoutdeparting from the spirit and scope of embodiments of the presentinvention. For example, a mesh network of two or more personal computers(PCs), similar electronic devices, or handheld portable devices,collaborating with one another to provide the functionality describedherein in association with the server 1200 may likewise be used withoutdeparting from the spirit and scope of embodiments of the presentinvention.

According to various embodiments, many individual steps of a process mayor may not be carried out utilizing the computer systems and/or serversdescribed herein, and the degree of computer implementation may vary, asmay be desirable and/or beneficial for one or more particularapplications.

FIG. 9B provides an illustrative schematic representative of a mobiledevice 1300 that can be used in conjunction with various embodiments ofthe present invention. Mobile devices 1300 can be operated by variousparties. As shown in FIG. 9B, a mobile device 1300 may include anantenna 1312, a transmitter 1304 (e.g., radio), a receiver 1306 (e.g.,radio), and a processing element 1308 that provides signals to andreceives signals from the transmitter 1304 and receiver 1306,respectively.

The signals provided to and received from the transmitter 1304 and thereceiver 1306, respectively, may include signaling data in accordancewith an air interface standard of applicable wireless systems tocommunicate with various entities, such as the server 1200, thedistributed devices 1110, 1120, and/or the like. In this regard, themobile device 1300 may be capable of operating with one or more airinterface standards, communication protocols, modulation types, andaccess types. More particularly, the mobile device 1300 may operate inaccordance with any of a number of wireless communication standards andprotocols. In a particular embodiment, the mobile device 1300 mayoperate in accordance with multiple wireless communication standards andprotocols, such as GPRS, UMTS, CDMA2000, 1×RTT, WCDMA, TD-SCDMA, LTE,E-UTRAN, EVDO, HSPA, HSDPA, Wi-Fi, WiMAX, UWB, IR protocols, Bluetoothprotocols, USB protocols, and/or any other wireless protocol.

Via these communication standards and protocols, the mobile device 1300may according to various embodiments communicate with various otherentities using concepts such as Unstructured Supplementary Service data(USSD), Short Message Service (SMS), Multimedia Messaging Service (MMS),Dual-Tone Multi-Frequency Signaling (DTMF), and/or Subscriber IdentityModule Dialer (SIM dialer). The mobile device 1300 can also downloadchanges, add-ons, and updates, for instance, to its firmware, software(e.g., including executable instructions, applications, programmodules), and operating system.

According to one embodiment, the mobile device 1300 may include alocation determining device and/or functionality. For example, themobile device 1300 may include a GPS module adapted to acquire, forexample, latitude, longitude, altitude, geocode, course, and/or speeddata. In one embodiment, the GPS module acquires data, sometimes knownas ephemeris data, by identifying the number of satellites in view andthe relative positions of those satellites.

The mobile device 1300 may also comprise a user interface (that caninclude a display 1316 coupled to a processing element 1308) and/or auser input interface (coupled to a processing element 308). The userinput interface can comprise any of a number of devices allowing themobile device 1300 to receive data, such as a keypad 1318 (hard orsoft), a touch display, voice or motion interfaces, or other inputdevice. In embodiments including a keypad 1318, the keypad can include(or cause display of) the conventional numeric (0-9) and related keys(#, *), and other keys used for operating the mobile device 1300 and mayinclude a full set of alphabetic keys or set of keys that may beactivated to provide a full set of alphanumeric keys. In addition toproviding input, the user input interface can be used, for example, toactivate or deactivate certain functions, such as screen savers and/orsleep modes.

The mobile device 1300 can also include volatile storage or memory 1322and/or non-volatile storage or memory 1324, which can be embedded and/ormay be removable. For example, the non-volatile memory may be ROM, PROM,EPROM, EEPROM, flash memory, MMCs, SD memory cards, Memory Sticks,CBRAM, PRAM, FeRAM, RRAM, SONOS, racetrack memory, and/or the like. Thevolatile memory may be RAM, DRAM, SRAM, FPM DRAM, EDO DRAM, SDRAM, DDRSDRAM, DDR2 SDRAM, DDR3 SDRAM, RDRAM, RIMM, DIMM, SIMM, VRAM, cachememory, register memory, and/or the like. The volatile and non-volatilestorage or memory can store databases, database instances, databasemapping systems, data, applications, programs, program modules, scripts,source code, object code, byte code, compiled code, interpreted code,machine code, executable instructions, and/or the like to implement thefunctions of the mobile device 1300.

The mobile device 1300 may also include one or more of a camera 1326 anda mobile application 1330. The camera 1326 may be configured accordingto various embodiments as an additional and/or alternative datacollection feature, whereby one or more items may be read, stored,and/or transmitted by the mobile device 1300 via the camera. The mobileapplication 1330 may further provide a feature via which various tasksmay be performed with the mobile device 1300. Various configurations maybe provided, as may be desirable for one or more users of the mobiledevice 1300 and the system 1020 as a whole.

It will be appreciated that many variations of the above systems andmethods are possible, and that deviation from the above embodiments arepossible, but yet within the scope of the claims. Many modifications andother embodiments of the invention set forth herein will come to mind toone skilled in the art to which these inventions pertain having thebenefit of the teachings presented in the foregoing descriptions and theassociated drawings. Such modifications may, for example, involve usinga different source of ray gun than the exemplified electron beam such aslaser beam. Other materials than metallic powder may be used such aspowders of polymers and powder of ceramics. Therefore, it is to beunderstood that the inventions are not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for purposes of limitation.

1. A method for forming a three-dimensional article through successivefusion of parts of a powder bed, which parts correspond to successivecross sections of the 3-dimensional article, said method comprising thesteps of: providing a model of said 3-dimensional article; applying afirst powder layer on a work table; directing an electron beam from anelectron beam source over said work table, said directing of saidelectron beam causing said first powder layer to fuse in first selectedlocations according to said model, so as to form a first part of a crosssection of said three dimensional article, and intensity modulatingX-rays from said powder layer or from a clean work table with apatterned aperture modulator and a patterned aperture resolver, whereina verification of at least one of a size, position, scan speed, or shapeof the electron beam is achieved by comparing detected intensitymodulated X-ray signals with saved reference values.
 2. The methodaccording to claim 1, wherein: said step of providing said modelcomprises storing said model within one or more memory storage areas;and one or more of said applying, directing, and intensity modulatingsteps are performed via at least one computer processor.
 3. The methodaccording to claim 1, wherein said X-rays are detected while fusing saidthree-dimensional article.
 4. The method according to claim 1, whereinsaid X-rays are detected during application of powder material.
 5. Themethod according to claim 1, wherein said X-rays are detected from astart plate before starting to manufacture said three-dimensionalarticle.
 6. The method according to claim 1, wherein said X-rays aredetected during a preheating step for elevating said powder layer to apredetermined temperature interval.
 7. The method according to claim 1,wherein said X-rays are detected at least once for each layer in thethree-dimensional article.
 8. The method according to claim 1, furthercomprising the steps of: adjusting at least one setting for controllingsaid electron beam in case of said deviation from a detected x-raysignal from a reference value being larger than a predetermined value;and repeating the intensity modulation and adjusting steps until saiddeviation is smaller than said predetermined value.
 9. The methodaccording to claim 8, wherein said reference value is achieved beforestarting the manufacture of the three-dimensional article from areference pattern provided on a reference plate.